Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int n, m, a[101][101];
int row1[101], col1[101], row2[101], col2[101];
void print(int r[], int c[]) {
  for (int i = 0; i < n; i++) {
    while (r[i]) {
      cout << "row " << i + 1 << '\n';
      r[i]--;
    }
  }
  for (int i = 0; i < m; i++) {
    while (c[i]) {
      cout << "col " << i + 1 << '\n';
      c[i]--;
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  cin >> n >> m;
  int ans1 = 0, ans2 = 0;
  for (int i = 0; i < m; i++) {
    col2[i] = 700;
  }
  for (int i = 0; i < n; i++) {
    int mn = 700;
    for (int j = 0; j < m; j++) {
      cin >> a[i][j];
      col2[j] = min(col2[j], a[i][j]);
      mn = min(mn, a[i][j]);
    }
    row1[i] = mn;
    ans1 += row1[i];
  }
  for (int i = 0; i < m; i++) {
    col1[i] = a[0][i] - row1[0];
    ans1 += col1[i];
    ans2 += col2[i];
  }
  for (int i = 0; i < n; i++) {
    row2[i] = a[i][0] - col2[0];
    ans2 += row2[i];
  }
  bool ok = true;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (row1[i] + col1[j] != a[i][j]) {
        ok = false;
      }
    }
  }
  if (ok == false) {
    cout << "-1";
    return 0;
  }
  int ans = min(ans1, ans2);
  cout << ans << '\n';
  if (ans == ans1) {
    print(row1, col1);
  } else {
    print(row2, col2);
  }
  return 0;
}